With advancement of the information society and rapid growth of the communication popularization rate, mobile communication terminals having a touch screen such as smartphones have become indispensable to the modern people's life. However, although they bring about conveniences in the life, the smartphones sometimes also cause troubles, and the most common trouble is mistaken dialing by an inadvertent keystroke: when the user puts the smartphone into a pocket of the clothes with the screen being unlocked, it is very likely that the dial keypad will be activated to cause a mistaken dialing due to contact of the smartphone with some other object. This not only causes troubles to the user (and to the called party), but also incurs unnecessary communication fees.
Currently, there are mainly two methods to prevent mistaken dialing: one is to additionally make dialing judgement, that is, a dialog box is popped up each time a phone number is selected and dialed so that a mistaken dialing is prevented through “OK” or “Cancel” options on the dialog box. The other method is to determine whether there is a voice speech after a call has been successfully dialed, that is, it is detected whether there is an input of a user's voice speech when a call is dialed, and if no audio signal is detected within a preset time, then the call is terminated automatically.
However, the first method might still cause a mistaken dialing due to a second mis-touch that falsely selects the “OK” option on the dialog box, so it cannot absolutely prevent the mistaken dialing and the mistaken dialing prevention effect is unsatisfactory. On the other hand, the second method is only able to prevent long-time calling after the butt call has been dialed (i.e., to prevent long-time lasting of the butt call) but cannot prevent the mistaken dialing action in a true sense; in other words, the judgement is made after the butt call has been successfully dialed, and this not only causes embarrassment to the called party but also wastes the communication fee of the calling party.